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Discussion Starter · #1 ·
So I noticed my service engine light came on and was flashing when I left this morning to my commute to work. I had no symptoms on the way. On my commute home the Transmission Started Shifting VERY hard on the automatic 2.2 2008 cobalt. Everytime it shifted the entire car would shake. When I got towards my house I stopped at autozone and had them run an OBD II test and it came up with a code P1811-00 ( Shift time excceeded with maximum adaptive pressure) I called four shops and they told me with that code it is 95 percent likely I need a transmission overhaul.

So i brought it home put it in the garage and started researching a bit and decided to perform some procedures

-removed negative bat terminal to reset ecm
-Removed two ground cables on the front of the transmission and wirebrushed terminal and contact points. used contact cleaner

-removed cannon plug from the front of the transmission cleaned with contact cleaner
- looked at sleeving near the ground lug where chaffing is typically found, I found no wire chaffing
-found the cold air intake was squeezed restricting airflow to the MAF, fixed it
-Cleaned MAF with with Intake cleaner
-Cleaned electrical conntector to MAF with Contact cleaner
-reset the ECM again
-checked all wires to ensure good contact to the groundlug of the tranny

I then Drove the car for an hour on the city and freeway. stopping and going frequently to work the transmission. It was RUNNING PERFECT! no more hard shifting, In the back of my mind I think I fixed it.

BUT

The Light is still illuminated and flashing when I turn the vehicle on and off even though there are no longer symptoms of hard shifting.

I plan to drain the transmission fluid and look to see if there are any metal flakes.


On this car, this code P1811-00 says

Causes
  • Failing pressure control solenoid/EPC solenoid
  • Worn clutches
  • Worn accumulators
  • Excessive valve body wear
  • Malfunctioning MAF sensor causing lowered commanded line pressure
Now the car is symptomless and still showing the light. (I would assume the same code)

Are there any master mechanic opinions on this situation as to why the light is remaining on but the symptoms disappeared? I would hate to have to sink 1500 dollars into the car.
 

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Registered
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3 Posts
Discussion Starter · #2 ·
So I noticed my service engine light came on and was flashing when I left this morning to my commute to work. I had no symptoms on the way. On my commute home the Transmission Started Shifting VERY hard on the automatic 2.2 2008 cobalt. Everytime it shifted the entire car would shake. When I got towards my house I stopped at autozone and had them run an OBD II test and it came up with a code P1811-00 ( Shift time excceeded with maximum adaptive pressure) I called four shops and they told me with that code it is 95 percent likely I need a transmission overhaul.

So i brought it home put it in the garage and started researching a bit and decided to perform some procedures

-removed negative bat terminal to reset ecm
-Removed two ground cables on the front of the transmission and wirebrushed terminal and contact points. used contact cleaner

-removed cannon plug from the front of the transmission cleaned with contact cleaner
- looked at sleeving near the ground lug where chaffing is typically found, I found no wire chaffing
-found the cold air intake was squeezed restricting airflow to the MAF, fixed it
-Cleaned MAF with with Intake cleaner
-Cleaned electrical conntector to MAF with Contact cleaner
-reset the ECM again
-checked all wires to ensure good contact to the groundlug of the tranny

I then Drove the car for an hour on the city and freeway. stopping and going frequently to work the transmission. It was RUNNING PERFECT! no more hard shifting, In the back of my mind I think I fixed it.

BUT

The Light is still illuminated and flashing when I turn the vehicle on and off even though there are no longer symptoms of hard shifting.

I plan to drain the transmission fluid and look to see if there are any metal flakes.


On this car, this code P1811-00 says

Causes
  • Failing pressure control solenoid/EPC solenoid
  • Worn clutches
  • Worn accumulators
  • Excessive valve body wear
  • Malfunctioning MAF sensor causing lowered commanded line pressure
Now the car is symptomless and still showing the light. (I would assume the same code)

Are there any master mechanic opinions on this situation as to why the light is remaining on but the symptoms disappeared? I would hate to have to sink 1500 dollars into the car.
I will run the OBD II again as soon as autozone opens
 
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